Since you've mentioned that firmware and everything have been up to date. Have you seen this article from them about Neo's upgrade last year?
(https://support.ledger.com/hc/en-us/articles/115005530425-Neo-N3-NEO-?support=true)
If that guide still doesn't work for you, I guess you should go and seek help from their subreddit.
(https://www.reddit.com/r/ledgerwallet/)